Just thinking about someone else other than your partner is classed as cheating, according to one in five people.

A survey for dating site Ashley Madison has revealed what actions people consider to count as infidelity.

While some are obvious, even what goes on in your head rather than in the bedroom could get you into serious trouble with your partner.

Isabella Mise, director of communications at Ashely Madison said: "Modern monogamy is becoming more and more vague so it really boils down to communication between couples and negotiating the terms of a marriage in an open way.